RE: blob-cvs-commit digest, Vol 1 #230 - 4 msgs

[Yamijala S. <Sri...@si...>]

Thank you very much Stefan.You gave me precisely the clarification i needed.

Regards
Sridhar

Message: 4
Date: Fri, 12 Sep 2003 15:09:18 +0200
From: ste...@el...
To: blo...@li...
Subject: Re: blob...arch specific files
Reply-To: ste...@el...
Organization: Eletztrick Computing

On Thu, Sep 11, 2003 at 10:32:59AM +0530, Yamijala Sridhar wrote:
> Thanks Stefan and Russ...the board is SA-1110 based but how do i know
which
> type it is: 
> i.e., how do i know whether it is "Assabet" / "Neponset" / "h3600" /
> "creditlart" / "system3" or any other type?
> Sorry for the confusion.I need another clarification.On what basis are the
> declarations for the 
> various addresses and lengths in <include/blob/arch/arch.h> made ?
> Could anyone pls guide me.

Ok.

"assabet", "neponset" .... are all specific boards which use the
SA1110 processor. But these boards are all quite different. They use
for ex. different SDRAM chips, different board glue logic, some
have additional peripheral hardware built in (Compact Flash, LCD panels,
etc).

BLOBs part in booting linux are:
	- set up memory correctly
	- find a way to load the kernel image to RAM, and do that
	- find a way to load a initial ramdisk to memory
	- set up a structure in RAM to tell the kernel what BLOB found out
so far
	- finally, start the linux kernel by jumping to a specific address
in memory.

Almost all of the above steps require _exact_ knowledge of the specific
hardware
BLOB runs on (not only the processor, but also how SDRAM is wired etc.).

That's why BLOB supports different "boards". A "board" in this context
means:
	- processor type info
	- memory setup info
	- serial port setup info
	- kernel info (where to load from, where to put into RAM)
	- flash type and setup info
	- other hardware info

So, to be able to use BLOB on your "board", you'll have to first get the
above information, understand it, and then try to teach BLOB to recognize
your "board". Thats what blob/doc/proting.txt is for.

You'll definitely need the schematics and all other hardware information of
your
board you can get. Then compare what you have with other board setups, and
choose the
one which matches most (porobably assabet, thats the INTEL reference
implementation, or
Lart or HackKit, they're rather simple), copy the parts and hack support for
your board in.

Hope this helps,
	Stefan

-- 
Eletztrick Computing - Customized Linux Development
Stefan Eletzhofer, Marktstrasse 43, DE-88214 Ravensburg
http://www.eletztrick.de